1. Field of the Invention
This invention relates to apparatus for chronographic display and in particular to a clock or a watch in which multiple patterns rotate in correspondence to the passage of time, producing various animated moire images.
2. Discussion of Prior Art
There are numerous prior art timepieces that use one or more partially transparent or translucent discs or plates in place of one or more of the standard linear hands to create visual effects. While some of these effects are pleasant or amusing to view, the lack of quantity and variety of effects, as well as certain effects that produce uncomfortable visual stimulus, results in a display that becomes uninteresting after a short time. This is due in large part to the inherent limitations of each device or design. Some of the prior art timepieces use a pair of polarized plates such as in French patent 1,127,795, to INVICTA, (Societe Anonyme) 1956, Dec. 24, which when rotated, create a cancellation effect that blocks reflected light twice per rotation, causing a vibrant flashing effect. Timepieces that use plates printed with translucent sections of color can produce pleasant color blending effects when rotated, especially if color gradients are used, as in U.S. Pat. No. 3,803,831, to Joseph Horzick, 1974, Apr. 16. However, these effects are very subtle and if used exclusively, tend to be only mildly stimulating. Much of the prior art in the field falls into the category of plates with decorative designs, which are usually figurative shapes, as in an airplane that rotates around the dial, or ornamental shapes. For example, U.K. patent 757,036, to Ernest Bornel, 1956, Sep. 12, shows a timepiece with a pair of plates having a sinusoidal line pattern, similar in shape to the spokes of a decorative wagon wheel. One of the plates is printed in a mirror image or mounted in reverse for contrast. These reversed decorative shapes when rotated, produce an unchanging, constant movement effect. In another embodiment, Bornel also uses plates printed with large geometric shapes that alternately hide and reveal similar geometric shapes. While these combined figures can be visually interesting because of their shapes, the optical effects that are produced are minimal.
Another area of chronographic display is in the area of lenticular optics, which are small optical lenses embossed on a surface. One or more overlapped lenticular plates when rotated, will produce a wavy, distorted image. This is achieved by the refractive lens-like structure of the material. While this can create a variety of patterns, especially if there is a graphic image underneath the lenticular plates, it is generally unpleasant to view, except briefly. This is due to the innate blurry, out of focus nature of the optics. Complexity in manufacturing and higher material cost adds to the drawbacks in the use of this media.